The middle to late Miocene has been regarded as a time of extensive ice-sheet growth (Serravallian, 14.8-11.2 Ma) followed by a period of ice-sheet stability (Tortonian, 11.2-7.1 Ma). Sea level curves created using sequence stratigraphy along with oxygen isotope records serving as ice volume proxies have been the main evidence for this. Paired Mg/Ca and delta-18O measurements of benthic foraminifera present an alternative method for determining ice volumes. This method derives paleotemperatures using Mg/Ca temperature calibrations for calcite. The calculated paleotemperatures can be used to correct oxygen isotope records for temperature effects. The result is a record that should be solely dependent upon ice volume. If deep-water temperatures and ice-sheet growth/decay vary with one another, then the temperature and ice volume curves produced using paired Mg/Ca and delta 18-O measurements should be parallel.
This study proposes to produce ice volume and deep-sea temperature curves for a period covering ~13-9.5 Ma (late Serravallian to mid Tortonian) using paired Mg/Ca and delta-18O measurements of benthic foraminifera from the equatorial Indian Ocean. The benthic foraminifera will be taken from cores of the Ocean Drilling Program (ODP) site 714A (2042 meters water depth) near the Maldives. A previous study done by Billups and Schrag (2001) has produced ice volume and deep-sea temperature curves for the Miocene using paired Mg/Ca and ?O18O measurements of benthic foraminifera from the Kerguelen Plateau in the Southern Ocean. They found discrepancies between deep-sea temperatures and ice volume during the Serravallian-Tortonian transition (~11.2 Ma) and the late Tortonian (~8.5 Ma). Deep-sea temperatures on the Kerguelen Plateau actually rose during periods of Antarctic ice-sheet expansion. The result was that the ice volume curve showed more extensive glaciations at ~11.2 and ~8.5 Ma than is seen in oxygen isotope records.
We hypothesize that our ice volume and deep-sea temperature curves will have discrepancies similar to those seen by Billups and Schrag (2001). If this is the case, then the results found by those authors will be shown to be global in nature, and not simply a consequence of a anomalous regional water mass. Some evidence for major sea level regressions during the middle to late Miocene already exists at the Maldives from seismic sequence stratigraphy and planktonic oxygen isotope records. We believe that the more robust ice volume determinant of paired Mg/Ca and delta 18O measurements will verify these regressions as major glacial events.
In conclusion, the proposed study has these aims:
1) Produce ice volume and deep-sea temperature curves for parts of the mid/late Miocene (~13-9.5 Ma).
2) Verify the applicability of paired Mg/Ca and delta 18O measurements to determine ice volume in the Neogene.
3) Determine the stability of the mid/late Miocene ice-sheet.

Some of the gas reservoirs in the northern Andaman Sea consist of isolated carbonate platforms developed on a volcanic high, in the Gulf of Martaban). The Indian plate is plunging below the Eurasian plate and the Gulf of Martaban is a back-arc basin. The commercial hydrocarbon reservoirs are developed above the volcanic arc. The seismic data available show two main carbonate episodes (Upper and Lower Burman, Limestone ) with an intermediate regional transgressive event, very similar to the broad sketch of the Maldives. Carbonates were finally drowned and covered by siliciclastics during Mid-Miocene time. For the Yadana structure, the Upper Burman limestone was studied in detail for economic reasons. Five wells partly cored by MOGE and four cored wells by Total Myanmar were studied. Two field excursions onshore Myanmar tried to ty a coeval analogue but failed to prove similar environments. The Maldives model was compared to the Yadana data and used to describe and to understand the general sedimentological model of the field. The quality of the Myanmar data and the results obtained from the Maldives data by A. Droxler and his PhD. students indicate that a detailed review of all the available seismic is required. This review should encompass the entire interval from the basement to the seal. It will provide a better understanding of the Oligocene/Miocene sea-level fluctuations, in the Yadana area calibrated to the sequence stratigraphy scheme developed in the Maldives. Then this general knowledge will be applied for the exploration program within the Tertiary interval from the Indian Ocean to the South China Sea. Particularly, this calibrated interpretation would be applied to scattered seismic data from the West Coast of India and the Pakistan.

TIMING AND AMPLITUDE OF OLIGOCENE/MIOCENE SEA LEVEL FLUCTUATIONS IN THE INNER SEA OF THE MALDIVE ARCHIPELAGO: AN INTRA-OCEANIC CARBONATE SYSTEM (EQUATORIAL INDIAN OCEAN)ODP Proposal #514
with Andrei Belopolsky

The Maldive Archipelago, an intra-oceanic tectonically relatively undisturbed carbonate system in the Central Indian Ocean, contrasts with the Bahamas and the Northeast Australia modern shallow-water tropical carbonate established along passive continental margins. The physiography of the Maldives stands out by its very large dimensions (over 800 km in length and 130 km in width) and its unique double chain of atolls separated by the shallow Maldive Inner Sea, a central basin not exceeding 600 m in water depth. Due to its location on a rigid part of the Indian Plate, minimum synsedimentary tectonic activity has been observed in the Maldive carbonate system since the Oligocene. In this proposal (No 514-Full3), we propose to drill an array of seven sites (MLA-1 to MLA-7) along a 21 km-long segment of a Shell SM89-E130 MCS line. This line is part of a dense (line spacing ranging from 2 to 4.5 km) 1989 2D grid (6000 km of seismic lines), acquired by Royal Dutch Shell in 1989 in the Maldive Inner Sea. This seismic grid is groundtruthed by ARI-1, a 3365 m-deep well that penetrated the entire Inner Sea sedimentary package. This comprehensive industrial MCS grid and ARI-1 well form an invaluable and unique data set to identify the Oligocene/Miocene sedimentary sequences and interpret their geometries, lateral variations, and vertical shifts, in a sequence stratigraphic framework. The site transect is proposed to be drilled across a seismically well imaged late Oligocene backstepping carbonate platform margin which evolved, after being almost completely drowned in the early Miocene, into a well-developed middle Miocene prograding platform margin. This drilling proposal will greatly help to compare and contrast existing high resolution benthic Oligocene-Miocene open marine ?O18O records, the best available sea level proxies, with the timing, amplitudes, and, therefore, rates of late Oligocene and Miocene eustatic sea level fluctuations established in a sequence stratigraphic framework. This proposal offers the unique opportunity to test the existence of the major !?30 Ma!? sea level fall of the Haq et al. (1987) eustatic chart at the early/late Oligocene boundary in nannofossils zone NP 24 and the subsequent dramatic sea level transgression in the late Oligocene and early Miocene. Moreover, the proposal will tie existing high resolution benthic Miocene delta18O records with 3th-to-4th-order prograding sedimentary sequences in order to define the timing and amplitude of the middle Miocene sea level fluctuations, a time interval characterized by a systematic growth of the Antarctic ice sheet.

This proposal, related to oil recovery from the ?La Concepcion? oil field has distinct objectives: the analyses of the carbonates deposits of the Cogollo Group (Mid Cretaceous) This objective will enhance the recovery of known but undeveloped oil and gas reserves from the Cogollo Group. The proposed research will focus on establishing the sequence stratigraphy framework in the available 3D seismic data sets to study the stacking of the sedimentary bodies and the lateral and vertical distribution of the seismic facies. The proposed research will focus on establishing the sequence stratigraphy framework in the available 3D seismic data sets to study the stacking of the sedimentary bodies and the lateral and vertical distribution of the seismic facies. The research will also focus on in relationship between the sedimentology and the petrophysical characterization of the rocks and the oil production potential

Research Statement

My past and current research programs involve detailed studies of carbonate
periplatform sedimentary records and environments. Areas where research has been and is conducted include
the Nicaragua Rise and Belize (Caribbean Sea), the Gulf of Mexico, the Bahamas (Northwestern Atlantic Ocean), the Maldives
(equatorial Indian Ocean), and
the Queensland Plateau/Great Barrier Reef (Southwest Pacific Ocean).

My current students and I are involved in comparative research programs of
Holocene, Pleistocene, and Neogene sediments deposited in deep environments
surrounding shallow carbonate platforms. We are focusing our studies on:

(1) processes related to recent carbonate sedimentation and

(2) the understanding of variations through time of carbonate mineralogy, micropaleontology and geochemistry
in periplatform sediments with direct global and regional implications with respect to
paleoceanography, paleoclimatology, and paleoecology.

Another objective of our research is to better understand the Cenozoic,
especially Neogene, evolution of modern carbonate platforms by means of
bathymetric and high resolution seismic surveys, coring and dredging, as
well as drilling. In the past ten years, I have been directly involved with
the Ocean Drilling Program (ODP) and have participated as sedimentologist at
four ODP Legs, Leg 101 in the Bahamas (1985), Leg 115 in the Maldives (1987),
Leg 133 in Northeast Australia (1990), and Leg 165 in the Caribbean (1996).
With my current graduate students, I am working on:

Although numerous studies have examined carbonate preservation and dissolution in pelagic sediments greater than 2500 m water depth, there have been very few studies about such processes at intermediate water depths (500-2500 m). We are establishing high-resolution paleoceanographic records of Quaternary sediments recovered from ODP Leg 165 Sites 999 and 1000 in the Caribbean Sea to determine long-term variations in carbonate sediment preservation and to investigate the relationships between carbonate preservation/dissolution and intermediate water circulation. The Caribbean basin affords a unique opportunity to investigate these relationships because it plays an important role in global ocean circulation and because western Atlantic waters filling the basin are intermediate in origin, restricted by an 1800 m maximum sill depth.
The ultimate objective of this research project is to examine these carbonate preservation records to determine if there are any long-term cyclical patterns. Bassinot, et al. (1994) and Yatsuda, et al. (1993) proposed an oscillation in Quaternary carbonate preservation and dissolution in the Indian and Pacific Oceans with a periodicity of 425-550 kyr. The mechanism(s) for such an oscillation are still conjectural and difficult to constrain. The high-resolution records from ODP Sites 999 and 1000 will determine if a similar pattern is observed in the Caribbean Sea.

TIMING AND AMPLITUDE OF OLIGOCENE/MIOCENE SEA LEVEL FLUCTUATIONS IN THE INNER SEA OF THE MALDIVE ARCHIPELAGO: AN INTRA-OCEANIC CARBONATE SYSTEM (EQUATORIAL INDIAN OCEAN)ODP Proposal #514
with Andrei Belopolsky

The Maldive Archipelago, an intra-oceanic tectonically relatively undisturbed carbonate system in the Central Indian Ocean, contrasts with the Bahamas and the Northeast Australia modern shallow-water tropical carbonate established along passive continental margins. The physiography of the Maldives stands out by its very large dimensions (over 800 km in length and 130 km in width) and its unique double chain of atolls separated by the shallow Maldive Inner Sea, a central basin not exceeding 600 m in water depth. Due to its location on a rigid part of the Indian Plate, minimum synsedimentary tectonic activity has been observed in the Maldive carbonate system since the Oligocene. In this proposal (No 514-Full3), we propose to drill an array of seven sites (MLA-1 to MLA-7) along a 21 km-long segment of a Shell SM89-E130 MCS line. This line is part of a dense (line spacing ranging from 2 to 4.5 km) 1989 2D grid (6000 km of seismic lines), acquired by Royal Dutch Shell in 1989 in the Maldive Inner Sea. This seismic grid is groundtruthed by ARI-1, a 3365 m-deep well that penetrated the entire Inner Sea sedimentary package. This comprehensive industrial MCS grid and ARI-1 well form an invaluable and unique data set to identify the Oligocene/Miocene sedimentary sequences and interpret their geometries, lateral variations, and vertical shifts, in a sequence stratigraphic framework. The site transect is proposed to be drilled across a seismically well imaged late Oligocene backstepping carbonate platform margin which evolved, after being almost completely drowned in the early Miocene, into a well-developed middle Miocene prograding platform margin. This drilling proposal will greatly help to compare and contrast existing high resolution benthic Oligocene-Miocene open marine ?O18O records, the best available sea level proxies, with the timing, amplitudes, and, therefore, rates of late Oligocene and Miocene eustatic sea level fluctuations established in a sequence stratigraphic framework. This proposal offers the unique opportunity to test the existence of the major !?30 Ma!? sea level fall of the Haq et al. (1987) eustatic chart at the early/late Oligocene boundary in nannofossils zone NP 24 and the subsequent dramatic sea level transgression in the late Oligocene and early Miocene. Moreover, the proposal will tie existing high resolution benthic Miocene delta18O records with 3th-to-4th-order prograding sedimentary sequences in order to define the timing and amplitude of the middle Miocene sea level fluctuations, a time interval characterized by a systematic growth of the Antarctic ice sheet.

The middle to late Miocene has been regarded as a time of extensive ice-sheet growth (Serravallian, 14.8-11.2 Ma) followed by a period of ice-sheet stability (Tortonian, 11.2-7.1 Ma). Sea level curves created using sequence stratigraphy along with oxygen isotope records serving as ice volume proxies have been the main evidence for this. Paired Mg/Ca and delta-18O measurements of benthic foraminifera present an alternative method for determining ice volumes. This method derives paleotemperatures using Mg/Ca temperature calibrations for calcite. The calculated paleotemperatures can be used to correct oxygen isotope records for temperature effects. The result is a record that should be solely dependent upon ice volume. If deep-water temperatures and ice-sheet growth/decay vary with one another, then the temperature and ice volume curves produced using paired Mg/Ca and delta 18-O measurements should be parallel.
This study proposes to produce ice volume and deep-sea temperature curves for a period covering ~13-9.5 Ma (late Serravallian to mid Tortonian) using paired Mg/Ca and delta-18O measurements of benthic foraminifera from the equatorial Indian Ocean. The benthic foraminifera will be taken from cores of the Ocean Drilling Program (ODP) site 714A (2042 meters water depth) near the Maldives. A previous study done by Billups and Schrag (2001) has produced ice volume and deep-sea temperature curves for the Miocene using paired Mg/Ca and ?O18O measurements of benthic foraminifera from the Kerguelen Plateau in the Southern Ocean. They found discrepancies between deep-sea temperatures and ice volume during the Serravallian-Tortonian transition (~11.2 Ma) and the late Tortonian (~8.5 Ma). Deep-sea temperatures on the Kerguelen Plateau actually rose during periods of Antarctic ice-sheet expansion. The result was that the ice volume curve showed more extensive glaciations at ~11.2 and ~8.5 Ma than is seen in oxygen isotope records.
We hypothesize that our ice volume and deep-sea temperature curves will have discrepancies similar to those seen by Billups and Schrag (2001). If this is the case, then the results found by those authors will be shown to be global in nature, and not simply a consequence of a anomalous regional water mass. Some evidence for major sea level regressions during the middle to late Miocene already exists at the Maldives from seismic sequence stratigraphy and planktonic oxygen isotope records. We believe that the more robust ice volume determinant of paired Mg/Ca and delta 18O measurements will verify these regressions as major glacial events.
In conclusion, the proposed study has these aims:
1) Produce ice volume and deep-sea temperature curves for parts of the mid/late Miocene (~13-9.5 Ma).
2) Verify the applicability of paired Mg/Ca and delta 18O measurements to determine ice volume in the Neogene.
3) Determine the stability of the mid/late Miocene ice-sheet.

This proposal, related to oil recovery from the 'La Concepcion' oil field has distinct objectives: the analyses of the carbonates deposits of the Cogollo Group (Mid Cretaceous) This objective will enhance the recovery of known but undeveloped oil and gas reserves from the Cogollo Group. The proposed research will focus on establishing the sequence stratigraphy framework in the available 3D seismic data sets to study the stacking of the sedimentary bodies and the lateral and vertical distribution of the seismic facies. The proposed research will focus on establishing the sequence stratigraphy framework in the available 3D seismic data sets to study the stacking of the sedimentary bodies and the lateral and vertical distribution of the seismic facies. The research will also focus on in relationship between the sedimentology and the petrophysical characterization of the rocks and the oil production potential

TIMING AND AMPLITUDE OF OLIGOCENE/MIOCENE SEA LEVEL FLUCTUATIONS IN THE INNER SEA OF THE MALDIVE ARCHIPELAGO: AN INTRA-OCEANIC CARBONATE SYSTEM (EQUATORIAL INDIAN OCEAN)ODP Proposal #514
with Andrei Belopolsky

The Maldive Archipelago, an intra-oceanic tectonically relatively undisturbed carbonate system in the Central Indian Ocean, contrasts with the Bahamas and the Northeast Australia modern shallow-water tropical carbonate established along passive continental margins. The physiography of the Maldives stands out by its very large dimensions (over 800 km in length and 130 km in width) and its unique double chain of atolls separated by the shallow Maldive Inner Sea, a central basin not exceeding 600 m in water depth. Due to its location on a rigid part of the Indian Plate, minimum synsedimentary tectonic activity has been observed in the Maldive carbonate system since the Oligocene. In this proposal (No 514-Full3), we propose to drill an array of seven sites (MLA-1 to MLA-7) along a 21 km-long segment of a Shell SM89-E130 MCS line. This line is part of a dense (line spacing ranging from 2 to 4.5 km) 1989 2D grid (6000 km of seismic lines), acquired by Royal Dutch Shell in 1989 in the Maldive Inner Sea. This seismic grid is groundtruthed by ARI-1, a 3365 m-deep well that penetrated the entire Inner Sea sedimentary package. This comprehensive industrial MCS grid and ARI-1 well form an invaluable and unique data set to identify the Oligocene/Miocene sedimentary sequences and interpret their geometries, lateral variations, and vertical shifts, in a sequence stratigraphic framework. The site transect is proposed to be drilled across a seismically well imaged late Oligocene backstepping carbonate platform margin which evolved, after being almost completely drowned in the early Miocene, into a well-developed middle Miocene prograding platform margin. This drilling proposal will greatly help to compare and contrast existing high resolution benthic Oligocene-Miocene open marine ?O18O records, the best available sea level proxies, with the timing, amplitudes, and, therefore, rates of late Oligocene and Miocene eustatic sea level fluctuations established in a sequence stratigraphic framework. This proposal offers the unique opportunity to test the existence of the major !?30 Ma!? sea level fall of the Haq et al. (1987) eustatic chart at the early/late Oligocene boundary in nannofossils zone NP 24 and the subsequent dramatic sea level transgression in the late Oligocene and early Miocene. Moreover, the proposal will tie existing high resolution benthic Miocene delta18O records with 3th-to-4th-order prograding sedimentary sequences in order to define the timing and amplitude of the middle Miocene sea level fluctuations, a time interval characterized by a systematic growth of the Antarctic ice sheet.

Some of the gas reservoirs in the northern Andaman Sea consist of isolated carbonate platforms developed on a volcanic high, in the Gulf of Martaban). The Indian plate is plunging below the Eurasian plate and the Gulf of Martaban is a back-arc basin. The commercial hydrocarbon reservoirs are developed above the volcanic arc. The seismic data available show two main carbonate episodes (Upper and Lower Burman, Limestone ) with an intermediate regional transgressive event, very similar to the broad sketch of the Maldives. Carbonates were finally drowned and covered by siliciclastics during Mid-Miocene time. For the Yadana structure, the Upper Burman limestone was studied in detail for economic reasons. Five wells partly cored by MOGE and four cored wells by Total Myanmar were studied. Two field excursions onshore Myanmar tried to ty a coeval analogue but failed to prove similar environments. The Maldives model was compared to the Yadana data and used to describe and to understand the general sedimentological model of the field. The quality of the Myanmar data and the results obtained from the Maldives data by A. Droxler and his PhD. students indicate that a detailed review of all the available seismic is required. This review should encompass the entire interval from the basement to the seal. It will provide a better understanding of the Oligocene/Miocene sea-level fluctuations, in the Yadana area calibrated to the sequence stratigraphy scheme developed in the Maldives. Then this general knowledge will be applied for the exploration program within the Tertiary interval from the Indian Ocean to the South China Sea. Particularly, this calibrated interpretation would be applied to scattered seismic data from the West Coast of India and the Pakistan.

Although numerous studies have examined carbonate preservation and dissolution in pelagic sediments greater than 2500 m water depth, there have been very few studies about such processes at intermediate water depths (500-2500 m). We are establishing high-resolution paleoceanographic records of Quaternary sediments recovered from ODP Leg 165 Sites 999 and 1000 in the Caribbean Sea to determine long-term variations in carbonate sediment preservation and to investigate the relationships between carbonate preservation/dissolution and intermediate water circulation. The Caribbean basin affords a unique opportunity to investigate these relationships because it plays an important role in global ocean circulation and because western Atlantic waters filling the basin are intermediate in origin, restricted by an 1800 m maximum sill depth.
The ultimate objective of this research project is to examine these carbonate preservation records to determine if there are any long-term cyclical patterns. Bassinot, et al. (1994) and Yatsuda, et al. (1993) proposed an oscillation in Quaternary carbonate preservation and dissolution in the Indian and Pacific Oceans with a periodicity of 425-550 kyr. The mechanism(s) for such an oscillation are still conjectural and difficult to constrain. The high-resolution records from ODP Sites 999 and 1000 will determine if a similar pattern is observed in the Caribbean Sea.

Although numerous studies have examined carbonate preservation and dissolution in pelagic sediments greater than 2500 m water depth, there have been very few studies about such processes at intermediate water depths (500-2500 m). We are establishing high-resolution paleoceanographic records of Quaternary sediments recovered from ODP Leg 165 Sites 999 and 1000 in the Caribbean Sea to determine long-term variations in carbonate sediment preservation and to investigate the relationships between carbonate preservation/dissolution and intermediate water circulation. The Caribbean basin affords a unique opportunity to investigate these relationships because it plays an important role in global ocean circulation and because western Atlantic waters filling the basin are intermediate in origin, restricted by an 1800 m maximum sill depth.
The ultimate objective of this research project is to examine these carbonate preservation records to determine if there are any long-term cyclical patterns. Bassinot, et al. (1994) and Yatsuda, et al. (1993) proposed an oscillation in Quaternary carbonate preservation and dissolution in the Indian and Pacific Oceans with a periodicity of 425-550 kyr. The mechanism(s) for such an oscillation are still conjectural and difficult to constrain. The high-resolution records from ODP Sites 999 and 1000 will determine if a similar pattern is observed in the Caribbean Sea.

The middle to late Miocene has been regarded as a time of extensive ice-sheet growth (Serravallian, 14.8-11.2 Ma) followed by a period of ice-sheet stability (Tortonian, 11.2-7.1 Ma). Sea level curves created using sequence stratigraphy along with oxygen isotope records serving as ice volume proxies have been the main evidence for this. Paired Mg/Ca and delta-18O measurements of benthic foraminifera present an alternative method for determining ice volumes. This method derives paleotemperatures using Mg/Ca temperature calibrations for calcite. The calculated paleotemperatures can be used to correct oxygen isotope records for temperature effects. The result is a record that should be solely dependent upon ice volume. If deep-water temperatures and ice-sheet growth/decay vary with one another, then the temperature and ice volume curves produced using paired Mg/Ca and delta 18-O measurements should be parallel.
This study proposes to produce ice volume and deep-sea temperature curves for a period covering ~13-9.5 Ma (late Serravallian to mid Tortonian) using paired Mg/Ca and delta-18O measurements of benthic foraminifera from the equatorial Indian Ocean. The benthic foraminifera will be taken from cores of the Ocean Drilling Program (ODP) site 714A (2042 meters water depth) near the Maldives. A previous study done by Billups and Schrag (2001) has produced ice volume and deep-sea temperature curves for the Miocene using paired Mg/Ca and ?O18O measurements of benthic foraminifera from the Kerguelen Plateau in the Southern Ocean. They found discrepancies between deep-sea temperatures and ice volume during the Serravallian-Tortonian transition (~11.2 Ma) and the late Tortonian (~8.5 Ma). Deep-sea temperatures on the Kerguelen Plateau actually rose during periods of Antarctic ice-sheet expansion. The result was that the ice volume curve showed more extensive glaciations at ~11.2 and ~8.5 Ma than is seen in oxygen isotope records.
We hypothesize that our ice volume and deep-sea temperature curves will have discrepancies similar to those seen by Billups and Schrag (2001). If this is the case, then the results found by those authors will be shown to be global in nature, and not simply a consequence of a anomalous regional water mass. Some evidence for major sea level regressions during the middle to late Miocene already exists at the Maldives from seismic sequence stratigraphy and planktonic oxygen isotope records. We believe that the more robust ice volume determinant of paired Mg/Ca and delta 18O measurements will verify these regressions as major glacial events.
In conclusion, the proposed study has these aims:
1) Produce ice volume and deep-sea temperature curves for parts of the mid/late Miocene (~13-9.5 Ma).
2) Verify the applicability of paired Mg/Ca and delta 18O measurements to determine ice volume in the Neogene.
3) Determine the stability of the mid/late Miocene ice-sheet.

Youthful Belize Barrier Reef: Strengthening the Model for a Mid-Brunhes Global Establishment of Modern Barrier Reefs

During a late June 2002 transit from Panama to Cancun on the R/V Marion Dufresne, a spectacular 37.6 m-long piston core MD02-2532 was retrieved from a water depth of 333 m at 3 km in front of the central Belize Barrier Reef. The core penetrated the distal part of a seismic wedge, made up of five distinctive subunits, and the upper part of an underlying seismic unit characterized by sub-parallel seismic reflectors. The age of the oldest sediment at the bottom of the core ranges, based upon nannofossil assemblage, between 720 and 450 kyr. Moreover, nannostratigraphy analyses at 1.5 m sample intervals yield three nannofossil age markers, LAD of Pseudoemiliania lacunosa, FAD and the Acme zone of Emiliania huxleyi were identified between 22.5-24.0 m, 12.0-10.5 m, and 4.5-3.0 m, respectively. Early interpretation of shipboard color reflectance and magnetic susceptibility data sets, in addition to visual core description and smear slide observations, seem to identify in the upper 24 m of the core five distinct light subunits characterized by low magnetic susceptibility separated by four darker subunits characterized by high magnetic susceptibility. In contrast the lower 13 m of the core are characterized by calcareous oozes rich in angular quartz and lithogenic grains, and a magnetic susceptibility signature clearly distinct from the upper 24 m of the core. The five subunits in the upper 24 m of the core are interpreted to consist of distal barrier reef deposits and correspond to late Quaternary interglacial marine isotope stages 11, 9, 7, 5, and 1. Those five subunits overlie an early Brunhes mixed siliciclastic-carbonate unit representing a deep open continental shelf.

Future research on MD02-2532 will the a suite of analyses, including carbonate content and mineralogy, planktic oxygen and carbon stable isotopes, Mg/Ca ratio for sea surface water paleo-temperature estimates from planktic foraminifers, and macro and micro fauna identification, establishment of integrated stratigraphy based on oxygen isotope-stratigraphy, nannostratigraphy and foraminifers stratigraphy.

This research program on the origin of the Belize Barrier Reef has far reaching global implication. The establishment of the Australian Great Barrier Reef was recently dated to be Brunhes in age and was given an age of 600 +/- 280 ka. Moreover the coralgal Key Largo limestone overlying quartz-rich early Pleistocene shelf deposits in the Florida Keys was estimated to late Pleistocene age. The initial analyses of core MD02-2532 associated with results of earlier research along the Belize margin point out, therefore, that, as for other modern barrier reefs offshore Northeast Australia, and South Florida, the Belize Barrier Reef represents young (late Pleistocene) and thin carbonate sedimentary deposits covering a series of late Pliocene and early Pleistocene lowstand prograding siliciclastic paleo coastlines (deltas and possibly beach ridges). According to our model, these extraordinary findings can be explained by two unique, global, and systematic floodings of early Pleistocene lowstand tropical paleo fluvial plains during the onset of interglacial marine isotope stages 11 and 9. These two exceptionally high amplitude (more than 100 m) sea level transgressions are the first such transgressions since the onset of the main northern Hemisphere glaciations 2.8 Ma. Moreover, those mid-Brunhes high amplitude sea level transgressions and high-sea-level intervals dramatically contrast with the late Pliocene and early Pleistocene overall lowering of the marine base level tied to the establishment and the expansion of the northern hemisphere major continental ice sheets.

Latest Pleistocene drowned coralgal banks and mounds along the edge of the South Texas and Mississippi continental shelves. IODP Drilling Proposal 581. With Andrei Belopolsky

Southern and Baker Banks are currently drowned coralgal reefs about 40 to 50 m-thick on the edge of the South Texas Shelf 55 km offshore Corpus Christi. They are interpreted to have grown during the first half of last sea level transgression on top of topographic highs occurring along a Last Glacial Maximum lowstand siliciclastic paleo coastline. Contemporaneous and similar coral reef establishment, growth, and demise have been reported along the Mississippi-Alabama shelf margin. We are proposing to drill and analyze nine 60 to 100 m - deep boreholes along the edge of the South Texas and Mississippi-Alabama continental shelves. Although this drilling proposal is submitted based upon its sole scientific merit, this drilling program should be also considered as an exemplary scientific drilling activity in shallow water conditions to promote alternate drilling platform as being a full part of IODP. This drilling program could also be used as a feasibility test in using the highly maneuverable, 190-ft-long R/V Seaprobe I of Fugro-McClelland as an alternate drilling platform to drill coralgal edifices in water depths shallower than 120 m.

The detailed description of the different lithologies and depositional environments, the borehole logs, the geochemical analyses, and U/Th and 14C AMS dating of these nine cored sedimentary sequences will allow us to develop the following objectives:

(a) The drilled material will shed some new light on the enigmatic findings that coralgal edifices flourished on the edge of the South Texas and Mississippi-Alabama shelves during the first part of last deglaciation, an interval of time when conditions of sea surface temperature were and sea surface salinity were expected to be lower in the Gulf of Mexico, and rates of eustatic sea-level rise much faster than they are today;

(b) The drilled material will improve the resolution of the last deglacial sea-level history from late Glacial to the Younger Dryas, including the interval of the melt-water pulse 1A, from a passive margin environment less influenced by discontinuous tectonic activity as in the offshore Barbados,

(c) The drilled material will help us to better understand the sedimentary and biological processes involved with the origin (initial establishment), growth, and demise of carbonate reef tracts along the edge of siliciclastic shelves.

(d) The latest Pleistocene transgressive coralgal reefs on the edge of the South Texas Shelf can be studied as recent analogs for reefal reservoirs buried in siliciclastic shelves.

This proposal, related to oil recovery from the ?La Concepcion? oil field has distinct objectives: the analyses of the carbonates deposits of the Cogollo Group (Mid Cretaceous) This objective will enhance the recovery of known but undeveloped oil and gas reserves from the Cogollo Group. The proposed research will focus on establishing the sequence stratigraphy framework in the available 3D seismic data sets to study the stacking of the sedimentary bodies and the lateral and vertical distribution of the seismic facies. The proposed research will focus on establishing the sequence stratigraphy framework in the available 3D seismic data sets to study the stacking of the sedimentary bodies and the lateral and vertical distribution of the seismic facies. The research will also focus on in relationship between the sedimentology and the petrophysical characterization of the rocks and the oil production potential

Some of the gas reservoirs in the northern Andaman Sea consist of isolated carbonate platforms developed on a volcanic high, in the Gulf of Martaban). The Indian plate is plunging below the Eurasian plate and the Gulf of Martaban is a back-arc basin. The commercial hydrocarbon reservoirs are developed above the volcanic arc. The seismic data available show two main carbonate episodes (Upper and Lower Burman, Limestone ) with an intermediate regional transgressive event, very similar to the broad sketch of the Maldives. Carbonates were finally drowned and covered by siliciclastics during Mid-Miocene time. For the Yadana structure, the Upper Burman limestone was studied in detail for economic reasons. Five wells partly cored by MOGE and four cored wells by Total Myanmar were studied. Two field excursions onshore Myanmar tried to ty a coeval analogue but failed to prove similar environments. The Maldives model was compared to the Yadana data and used to describe and to understand the general sedimentological model of the field. The quality of the Myanmar data and the results obtained from the Maldives data by A. Droxler and his PhD. students indicate that a detailed review of all the available seismic is required. This review should encompass the entire interval from the basement to the seal. It will provide a better understanding of the Oligocene/Miocene sea-level fluctuations, in the Yadana area calibrated to the sequence stratigraphy scheme developed in the Maldives. Then this general knowledge will be applied for the exploration program within the Tertiary interval from the Indian Ocean to the South China Sea. Particularly, this calibrated interpretation would be applied to scattered seismic data from the West Coast of India and the Pakistan.

Research Statement

My past and current research programs involve detailed studies of carbonate
periplatform sedimentary records and environments. Areas where research has been and is conducted include
the Nicaragua Rise and Belize (Caribbean Sea), the Gulf of Mexico, the Bahamas (Northwestern Atlantic Ocean), the Maldives
(equatorial Indian Ocean), and
the Queensland Plateau/Great Barrier Reef (Southwest Pacific Ocean).

My current students and I are involved in comparative research programs of
Holocene, Pleistocene, and Neogene sediments deposited in deep environments
surrounding shallow carbonate platforms. We are focusing our studies on:

(1) processes related to recent carbonate sedimentation and

(2) the understanding of variations through time of carbonate mineralogy, micropaleontology and geochemistry
in periplatform sediments with direct global and regional implications with respect to
paleoceanography, paleoclimatology, and paleoecology.

Another objective of our research is to better understand the Cenozoic,
especially Neogene, evolution of modern carbonate platforms by means of
bathymetric and high resolution seismic surveys, coring and dredging, as
well as drilling. In the past ten years, I have been directly involved with
the Ocean Drilling Program (ODP) and have participated as sedimentologist at
four ODP Legs, Leg 101 in the Bahamas (1985), Leg 115 in the Maldives (1987),
Leg 133 in Northeast Australia (1990), and Leg 165 in the Caribbean (1996).
With my current graduate students, I am working on:

Research Statement

My past and current research programs involve detailed studies of carbonate
periplatform sedimentary records and environments. Areas where research has been and is conducted include
the Nicaragua Rise and Belize (Caribbean Sea), the Gulf of Mexico, the Bahamas (Northwestern Atlantic Ocean), the Maldives
(equatorial Indian Ocean), and
the Queensland Plateau/Great Barrier Reef (Southwest Pacific Ocean).

My current students and I are involved in comparative research programs of
Holocene, Pleistocene, and Neogene sediments deposited in deep environments
surrounding shallow carbonate platforms. We are focusing our studies on:

(1) processes related to recent carbonate sedimentation and

(2) the understanding of variations through time of carbonate mineralogy, micropaleontology and geochemistry
in periplatform sediments with direct global and regional implications with respect to
paleoceanography, paleoclimatology, and paleoecology.

Another objective of our research is to better understand the Cenozoic,
especially Neogene, evolution of modern carbonate platforms by means of
bathymetric and high resolution seismic surveys, coring and dredging, as
well as drilling. In the past ten years, I have been directly involved with
the Ocean Drilling Program (ODP) and have participated as sedimentologist at
four ODP Legs, Leg 101 in the Bahamas (1985), Leg 115 in the Maldives (1987),
Leg 133 in Northeast Australia (1990), and Leg 165 in the Caribbean (1996).
With my current graduate students, I am working on:

The transition from a passive to an active margin is of great geological significance and interest. During this transition, local tectonics and therefore basin subsidence rates and relative sea level fluctuations are modified, and, as a consequence, the origin and the distribution pattern of sediments become altered. Northwestern Venezuela exemplifies such a scenario whereby its Cretaceous passive margin was disturbed and modified by the collision of the Caribbean and South American plates beginning in the Late Cretaceous and peaking in the Paleocene-Eocene time frame. The geological evolution of the Lake Maracaibo region was subsequently modified from a passive to an active continental margin. Therefore, I propose for my Masters? research to integrate structural, sedimentological, and geophysical data in order to enhance our understanding of the transitional evolution of Lake Maracaico region from a passive to an active continental margin.

Initially, I am proposing to carry out a thorough structural interpretation using the 242 km2 of a 3D seismic cube from La Concepciun field in the Maracaibo basin of northwest Venezuela. Then, based on complete well log suites of about 10 wells and possibly cutting samples, I am proposing to develop a sequence stratigraphic framework for the Tertiary section, with a particular focus on the Paleocene mixed siliciclastic-carbonate of the Guasare Formation. I am proposing to establish the stacking patterns of individual sedimentary bodies and compare those pattern with the lateral and vertical distribution of the Guasare Fm. seismic facies. The ultimate goal of my proposed study will be to establish the relationship(s) between the sedimentology and the petrophysical characterization of the rocks to develop some reservoir characterization of the Guasare Fm. and place them in the context of the transitional evolution of Lake Maracaico region from a passive to an active continental margin.

B.E. Carson and A.W. Droxler "Mid-Brunhes First High Amplitude Transgression (s):
Platform Top and Shelf Contemporaneous Re-flooding Recorded on the Slopes of Great Bahama Bank and Central Belize Barrier Reef
." (2007)

Droxler, A.W. "Past Earth Climate Change in the Context of Current and Future Global Warming." (2007)

Droxler, Andre, Gianni Mallarino, Jason M. Francis, Jerry Dickens, Luc Beaufort, Samuel Bentley, Larry Peterson, and Bradley Opdyke "Early Part of Last Deglaciation: A Short Interval Favorable for the Building of Coralgal Edifices on the Edges of Modern Siliciclastic Shelves (Gulf of Papua and Gulf of Mexico)." (2006)

Dipanjan Mitra, Andre W. Droxler, Philippe Lapointe, and Arthur H. Saller ". Late Oligocene and Early Miocene Evolution of the Carbonate System in the Gulf of Martaban (Northern Andaman Sea): Comparison with the Maldives. Controls on Carbonate Platform and Reef Development II." Technical Program (June 19-22, 2005)

Droxler, A. W. and Belopolsky, A.V. "Model for the Establishment of Modern Atolls during the Mid Brunhes MIS 12 to MIS 11 Sea Level Transgression in the Maldive Archipelago (Equatorial Indian Ocean)." (Fall 2003)

Droxler, A. W. "The marine carbonate system during the mid-Brunhes unusually warm interval: A clear case of basin to shelf fractionation." Proceedings of the 6th International Conference on Paleoceanography (1998)

Roth M.J., Droxler, A.W., and Cameo, K. "The Caribbean carbonate crash at the middle to late Miocene transition and the establishment of the modern global thermohaline circulation." Proceedings of the Ocean Drilling Program, B (1998)

"Caribbean constraints on circulation between Atlantic and Pacific oceans over the past 40 million years." Tectonics, Circulation, and Climate in the Caribbean Gateway, Austin, TX. (March, 30-2006) With Kevin Burke

"Early Part of Last Deglaciation: A Short Interval Favorable for the Building of Coralgal Edifices on the Edges of Modern Siliciclastic Shelves (Gulf of Papua and Gulf of Mexico)
." AAPG 2006 Annual Meeting, Houston, Texas. (April 10, 2006) With Andre Droxler, Gianni Mallarino, Jason M. Francis, Jerry Dickens, Luc Beaufort, Samuel Bentley, Larry Peterson, and Bradley Opdyke

"Origin of Modern Atolls: A Direct Response to Sea Level Fluctuations in the Last 3 Million of Years. Revisiting Darwin's Theory on Atoll and Barrier Reef Formation linked to Subsidence of Volcanic Edifice." Dr. Bradley Opdyke, Australian National University, Canberra, Australia. (Feb 17, 2006)

"Increased Atmospheric CO2 concentration, Global Warming, and Modern Coral Reefs: a Geological Point of View of Current and Future Challenges for Coral Reefs." Kinkaid Middle School (7th Grade), Houston, TX.

"Mid Brunhes origin of modern atolls: a model developed in the Maldives and Moruroa atolls." EGU meeting Vienna, Special session on the honor of Wolfgang Schlager, Vienna, Austria.

"Neogene Evolution of the Mixed Carbonate/Siliciclastic Margin of the Gulf of Papua: Preliminary Results of Spring 2004 PANASH Cruise on the R/V Melville." Anadarko, The Woodlands, Texas.

"Origin of Modern Atolls: A Direct Response to Sea Level Fluctuations in the Last 3 Million of Years: Revisiting Darwin’s Theory on Atoll and Barrier Reef Formation linked to Subsidence of Volcanic Edifice." Weekly Seminar Series University of Delaware, University of Delaware.

"The Academic Test in last 25 years of The Vail Sea-Level Curve: the bias point of view of carbonates." Sequence Stratigraphy and Global Changes in Sea Level Symposium honoring Prof. Peter R. Vail; Co-sponsored by The Franklin Institute and the Department of Earth and Environmental Science of The University of Pennsylvan, University of Pennsylvania.

"Climate Change in the Next Century: Effects on the Maldives, Belize, and Australian Great Barrier Reefs." Lecture co-hosted by the Swiss Consulate of Houston and the Center for the Study of Environment and Society, Rice University. (November 11, 2009)

"Late Brunhes Sea Level-Induced Formation of Modern Atolls in the Maldive Archipelago (Equatorial Indian Ocean)." AAPG Meeting Annual Meeting, Invited Contribution for a special session on 'Selected Outstanding Presentations from around the World', Denver. (June 2001) With Belopolsky, A. V. and Aubert, O.

"Similarities Between a Sequence Stratigraphy Pattern Common to the Maldives and the Bahamas, and a Planktic Oxygen Isotope Record from the Equatorial Indian Ocean in the Miocene (19-9 Ma)." AGU Spring Meeting, Boston. (May 2001) With Belopolsky, A. V.and Vincent E.

"Temperature and Hydrological Changes in the Western Caribbean during the Last Glacial Cycle." 7th International Conference on Paleoceanography, Sapporo, Japan. (September 2001) With Schmidt, M.W., Spero, H.J., Lea, D.W.

"The Caribbean Carbonate Crash at the Middle to Late Miocene Transition: Linkage to the Establishment of the Modern Global Ocean Conveyor." AGU Spring Meeting, Boston. (May 2001) With Roth, J. M.

"The Obliquity Cycle of Nutricline Variations during the last 300,000 years in the Caribbean and the Bahama Bank ? The linkage to the High Latitude Climate." 7th International Conference on Paleoceanography, Sapporo, Japan. (September 2001) With Kameo, K., Watanabe, R., Mita, I., Shearer, M.C., and Sato, T.

"DARWIN and the Voyage of the BEAGLE:Revisiting Darwin?s Arguments for his Subsidence Theory on Atoll and Barrier Reef Formation." Rice University Continuing Studies and The Houston Museum of Natural Science, Houston,TX. (November 7, 2000)

"Late Brunhes Sea Level-Induced Formation of Modern Atolls in the Maldive Archipelago (Equatorial Indian Ocean)." AAPG International Meeting, Bali, Indonesia. (October 2000) With With Belopolsky, A.V. and Aubert, O

"Unusually Warm Climates during the Mid-Brunhes: Golden Ages for Carbonate Production." Invited Speaker, Weekly Seminar Series Dept. of Earth and Marine Siences, University of South Carolina. (October, 1998)

Collaborative Research: Late Quaternary Siliciclastic and Carbonate Sediments and Sediment Fluxes on the Slopes and
Basin Floors of the Ashmore and Pandora Troughs., NSF (07/08/05 -10/31/07)

Seismic Interpretation of a Grid of Industry and Academic Data Sets from the Shelf and Offshore Troughs of the Gulf of Papua and the Analyses of a Series of Three Piston Cores Total E&P, the Gulf of Papua, Total E&P (12/01/05 -03/31/08)